Quantitative studies on changes of decomposition rate, C/N ratio, N, K and organic C of bean residue during decomposition in desert ecosystem were carried out in Fukang, Xinjiang. Results showed that Accumulative decay rate and organic C decomposition rate of bean residue increased followed by the increasing of decomposition time. The decay rate in 0~1.5 month and 1.5~3 month were 18.9% and 18.7%, respectively. The total N increased gradually first, then kept on after 6 months. The total K decreased quickly at the first 1.5 month, then decreased slowly, then kept on after 3 months. The releasing amount and releasing rate of N were all minus. There was no releasing of N in the whole of decomposition. The releasing rate of K reached 75.8% in 1.5 months, then changed around 90%. The C/N ratio of decay remainders decreased quickly first, then didn’t change on the whole after 6 months, and finally it was 35.9.